Polyureas



United States Patent D 3,242,210 POLYUREAS John L. Dreher, Berkeley, andJudson E. Goodrich, San

Rafael, Calif, assignors to Chevron Research Company, a corporation ofDelaware No Drawing. Filed Mar. 16, 1965, Ser. No. 440,282 17 Claims.(til. 260-653) This application is a continuation-in-part of applicationSerial Nos. 84,511, filed Jan. 24, 1961; 109,827, filed May 15, 1961,both now abandoned; 210,559, filed July 17, 1962 and 312,357, filedSept. 30, 1963, all now abandoned.

This invention concerns novel polyureas and their use as greasethickening agents. More particularly, this invention concerns novelpolyureas of at least 4 urea groups having hydrocarbon terminal endmembers and their use as grease thickening agents.

There has been an increasing need for grease thickening agents which areoperable at elevated temperatures, that is, temperatures above 350 F.and preferably temperatures above 400 F. The need is a result of theincreasing speed and energy requirements of the jet age. Gears,bearings, and other moving parts are required to operate at greaterspeed and higher loads than have heretofore been required. This hasresulted in ever-increasing temperatures occurring in the area of themoving parts. For the most part, high temperature grease thickeningagents have been fatty acid salts. Illustrative of such thickeners whichprovide relatively high melting point grease compositions are thelithium soaps of various fatty acids. However, these fatty acid saltscatalyze the oxidation of the lubricant. At the higher temperatures ofoperation, the rapid oxidative degradation of the lubricant increasesthe frequency with which the old lubricant must be removed and newgrease lubricant applied to the moving surface.

Pursuant to this invention, grease thickening agents having relativelyhigh melting points (relatively high dropping points for the greases)are provided which are polyureas of the following formula:

(it i i i RNHTONHRWNHCNHRNH/ CNHRWNHCNHR wherein x is an integer of from1 to 3, R and R may be the same or different and are hydrocarbylene offrom 2 to 30 carbon atoms (hydrocarbylene is a divalent organic radicalcomposed solely of carbon and hydrogen which may be aliphatic, alicyclicor aromatic or combinations thereof, e.g., alkaryl, aralkyl, etc.,having its two free valences on different carbon atoms); R and R may bethe same or different and are hydrocarbyl of from 1 to 30 carbon atoms(hydrocarbyl is a monovalent organic radical composed solely of carbonand hydrogen which may be aliphatic, aromatic, or alicyclic orcombinations thereof, e.g., aralkyl, alkaryl, etc.).

The polyureas of the above formula are readily prepared by mixingdiisocyanates and diamines with monoisocyanates or monoamines in theproper proportions to form the desired polyurea. The polyureas of thisinvention find use as grease thickeners providing greases which areuseful at temperatures from about -l F. to 500 F. and remain unctuousafter long use, not becoming hard or brittle. The grease compositionsthus formed are extremely resistant to emulsification in water. Moreover, the polyureas are thickeners or gellants in a variety of fluids,particularly hydrocarbons, of low viscosity to form fire starters,paints, and the like.

The prefenred compositions of this invention have the following formula:

3,242,210 Patented Mar. 22, 1966 wherein x is an integer of from 1 to 3,preferably, 1, R

and R are the same or different and are hydrocarbyl of from 5 to 28carbon atoms, preferably of from 6 to 25 carbon atoms and R and R may bethe same or different and will be hydrocarbylene of from 2 to 26 carbonatoms, more usually of from 2 to 18 carbon atoms. It is furtherpreferred that in the tetraur-eas, the sum of the carbon atoms of R andR is in the range of 10 to 30 and the sum of the carbon atoms of R and Ris in the range of 12 to 40.

The monoamine or monoisocyanate used in the formation of the polyureawill form the terminal end group. As already indicated, these terminalend groups will be of from 1 to 30 carbon atoms, but are preferably offrom 5 to 28 carbon atoms and more desirably of from 6 to 25 carbonatoms. As already indicated, the substituent on the nitrogen is ahydrocarbon radical which may be aliphatic, aromatic or alicyclic, maybe aliphatically saturated or unsaturated, or may be combinations of thevarious types of hydrocarbon radicals.

Illustrative of various monoamines are pentylamine, hexylamine,heptylamine, octylamine, decylamine, dodecylamine, tetradecylamine,heX-adecylamine, octadecylamine, eicosylarnine, dodecenylamine,hexadecenylamine, octadecenylamine, octadecadienylamine, abietylamine,aniline, toluidine, naphthylamine, cumylamine, bornylamine,fenchylamine, tert.-butyl aniline, benzylamine, ,8- phenethylamine, etc.

Illustrative of monoisocyanates are hexylisocyanate, decylisocyanate,dodecylisocyanate, tetradecylisocyanate, hexadecylisocyanate,phenylisocyanate, cyclohexylisocyanate, Xyleneisocyanate,cumeneisocyanate, abietylisocyanate, cyclooctylisocyanate, etc.

The preferred aromatic terminal end groups are those of from 6 to 12carbon atoms. The preferred aliphatic terminal end groups are those offrom 10 to 20 carbon atoms.

The diamines and diisocyanates which form the internal hydrocarbonbridges between the areas are, as indicated, of from 2 to 30 carbonatoms, preferably from 2 to 26 carbon atoms and more desirably of from 2to 18 carbon atoms.

Illustrative of various diamines are ethylenediamine, propanediamine,butanediamine, hexadiamine, dodecanediamine, octanediamine,hexadecanediamine, cyclohexanecliamine, cyclooctanediamine,phenylenediamine, tol-uenediamine, xylenediamine, dianilinemethane,ditoluidinemethane, bisaniline, bistoluidine, etc.

Illustrative of diisocyanates are hexanediisocyanate,decanediisocyanate, octadecanediisocyanate, phenylenediisocyanate,toluenediisocyanate, bis(diphenylisocya nate), methylenebis(phenylisocyanate), etc.

The aromatic hydrocarbylene or bridging groups will generally be of fromabout 6 to 18 carbon atoms. The aliphatic hydrocarbylene or bridginggroups will generally the of from about 2 to 10 carbon atoms.

Preferably, the polyureas will have a polar/nonpolar balance. That is,there will be at least about 6 carbon atoms per urea group and moreusually about 8 carbon atoms per urea group, but fewer than 20 carbonatoms per urea group and more usually fewer than 16 carbon atoms perurea group.

The tetraureas of this invention have the following formula:

0 R NHilNHR NH NHR NH NHR NHlNHR wherein R R R and R are as definedpreviously.

The polyureas of this invention can be used as thickening agents to formgreases in a wide variety of oils of lubricating viscosity. Various baseoils include naphthenic base, parafiin base and mixed base minerallubricating oils; synthetic oils, such as polymers of propylene,butylene, etc., propylene oxide polymers, carboxylic acid esters, e.g.,isooctyl azelate, pentaerthyritol caproate or dipropylene glycoldipelagonate; silicon esters, such as tetraethyl silicate,hexa(4-methyl-2-pentoxy)disiloxane, etc.

When used as grease thickeners, the compounds described herein are usedin oils of lubricating viscosity in amounts sufficient to thicken theoil to the consistency of grease, that is, in amounts ranging from 5% to50% by weight, preferably, in amounts from 6 to 25% by weight.

The compositions of this invention may also be used with a wide varietyof hydrocarbon solvents as gellants. These include both aromaticsolvents such as benzene, toluene, xylene, or mixtures thereof as wellas aliphatic solvents, such as heptane, hexane, octane, nonane, d-ecane,etc. or mixtures thereof. When used as a gellant, the polyureas will bepresent in amount of at least about 0.5 weight percent, more usuallyfrom about 1 to 5 weight percent.

As indicated when preparing the polyureas, the monoamines or isocyanatesare merely brought together with the diisocyanates and diazmines in theproper proportion, preferably in the presence of an inert diluent.Usually, the vehicle to be thickened or gelled will be the preferreddiluent. It is not necessary that the diluent be a solvent for all thereactants. With a heterogeneous system, efficient stirring helps toinsure smooth reaction between the various reactants.

The temperature of the reaction will generally vary from about 20 C. toabout 100 C., more usually from about 20 C. to 75 C. The reaction itselfis exothermic and by starting at room temperature, elevated temperaturesare obtained. However, external heating or cooling may be desirable. Theconcentration of polyurea in the final product may vary from about 1 to50 weight percent, depending on the various reactants, the particularproduct desired, etc.

The following examples are offered by way of illustration and not by wayof limitation.

EXAMPLE 1.-PREPARATION OF TETRAUREA A mixture of 177.8 g. (0.711 mole)of diphenylmethane,, 4,4-diisocyanate and 350 ml. of methylethylketone(MEK) was heated to 150 F. This mixture was blended with 1,200 g. ofpentaerythritol caproate (Hercoflex 600). To this blend was added an MEKsolution of 38.5 g. (0.356 mole) of p-phenylenediamine, 98 g. (0.364mole) of Armeen 18D, which is described hereinbelow, and 37.8 g. (0.353mole) p-toluidine in 350 ml. of hot MEK with agitation. The whole blendwas heated to 300 F., at which temperature was added 49.7 g. ofcommercial oxidation inhibitors and 402.3 g. of pentaerythritolcaproate. The temperature was increased to 400 F., after which thecomposition was pan cooled, then milled twice at 4000 p.s.i. Theresulting thickened composition was useful as a grease and had an ASTMunworked penetration (P of 237 and a dropping point of 500+ F.

EXAMPLE 2.PREPARATION OF TETRAUREA A solution of 141.5 g. (0.566 mole)of diphenylmethane, 4,4'-diisocyanate in 350 ml. of methylethylketone(MEK) was blended with 1089 g. of diisooctylazelate with agitation. Tothis blend was added a solution of 56.1 g. (0.283 mole) of methylenedianiline, 152.2 g. (0.566 mole) of Armeen 18D in 350 ml. of warm MEK.After this blend had been heated to 300 F., there was added 36.8 g. ofcommercial oxidation inhibitors. The mixture was heated to 400 F., and364 g. of diisooctylazelate was added. After pan cooling, the resultingthickened composition was milled at 4000 p.s.i., yielding a greasethickened with 19% tetraurea, and having a P of 275 and a dropping pointof 500=+ F.

A sample of the tetraurea grease thickener of Example 2 hereinabove wasisolated by placing 50.34 g. of the grease for Example 2 in a Soxhletextractor for 72 hours with refluxing MEK. The cup was then dried invacuo, and on analysis the extract solid was found to contain thefollowing:

EXAMPLE 3.PREPARATION OF HEXAUREA A mixture of 10.8 g. (0.10 mole) ofmetaphenylene diamine, and 30.0 g. (0.10 mole) of a mixture of primaryamines having an average molecular weight of 300, was heated at 300 F.until a solution was obtained. This amine solution was added quicklywith rapid agitation to a mixture consisting of 41.7 g. (0.15 mole) ofdiphenylmethane, 4,4'-diisocyanate and 300 g. of a California parafiinicbase oil having a viscosity of 500 SSU at F. The resulting mixture wasstirred in a high speed Waring Blendor for 15 minutes, then heated in anoven at 350 F. for 3 hours, with an occasional mixing by hand. Themixture was cooled to ambient temperatures, then milled through anextrusion-type mill at 5600 p.s.i. After the addition of 75 g. of thesame oil described hereinabove, the thickened grease-type compositionwas milled twice at 5600 p.s.i.

The resulting grease, which contained 15.6% of the hexaurea, had an ASTMworked penetration (P of 294, and an ASTM dropping point of 473 F.

EXAMPLE 4.PREPARATION OF OCTAUREA A mixture of 16.2 g. (0.15 mole) ofmetaphenylenediamine and 300 g. (0.10 mole) of the same amine describedin Example 3 hereinabove, was heated at 300 F. until solution occurred.This hot' amine solution was added quickly with violent agitation to ablend consisting of 55.6 g. (0.20 mole) of diphenylmethane, 4,4-diisocyanate and 372 g. of a California parafiin base oil having aviscosity of 500 SSU at 100 F. The resulting blend was stirred at highspeed for 30 minutes, then heated in an oven at 350 F. for 3 hours, witha mixing by hand every 30 minutes. The grease was cooled to ambienttemperature, than milled twice through an extrusion-type mill at 5600p.s.i.

The finished grease, which contained 19.9% of the octaurea, had an ASTMworked penetration (P of 303, and an ASTM dropping point of 496 F.

EXAMPLE 5.PREPARATION OF TETRAUREA A mixture of 3.6 g. ofethylenediamine, 30 g. of Armeen T and 7 g. of an antioxidant was heatedat F. for 10 minutes, forming a homogenous solution. This solution wasadded quickly to a lubricating oil blend consisting of 223 g. of aCalifornia base oil having a viscosity of 480 SSU at 100 F., and 17.4 g.of on isocyanate (an 80/20 mixture of 2,4-toluenediisocyanate and2,6-toluenediisocyanate) with vigorous agitation in a Waring Blendor. Agel formed immediately. The resulting grease was removed from theblender, hand mixed, and milled at 8000 p.s.i.

The final grease which contained 12.5% thickening agent, had an ASTMWorked penetration (P of 290 and an ASTM dropping point of 505 F.

The following table illustrates a number of tetraureas prepared asdescribed in the prior examples. The tetraureas were formed in a varietyof oils of lubricating viscosity with varying chemical nature. The ASTMUnworked Penetration (P thetASTM Worked Penetration after 60 strokes inthe ASTM worker (P and in 1 Armeen 'l is principally an octadecenylamine sold by the Armour Company, Chicago, Ill.

many instances, the ASTM Dropping Point in degrees F. are reported.

Base oil L was a mixture of dipropylene glycol dipelargonate and apolypropylene oxide capped with an 1 In addition to the thickener, thesegreases contained from 1.4 to 2.1%

an oxidationinhibitor.

2 N o antioxidants were used.

It is evident from the above table, that excellent greases are obtainedhaving low penetrations and high dropping points.

The diisocyanates used in the preparation of the polyureas of Table Iare described as follows:

A diphenylmethane 4,4'-diisocya11ate;

B 3,3-dimethyldiphenylmethane 4,4'-diisocyanate; C 3,3-bitolylene4,4-diisocyanate;

D m-xylylene diisocyanate;

E 2,4-, 2,6-toluenediisocyanate (80/20).

The monoamines from which the R and R" radicals were derived aredescribed as follows:

(1) Octadecylamine sold as Armeen 18D by the Armour Company, Chicago,111.;

(2) A mixture of monoamines sold as Armeen HT by the Armour Company,Chicago, 111., containing hexadecylamine, 70% octadecylamine and 5%octaby weight of n-butyl group and a hydroxyl radical and having amolecular weight of about 500;

Base oil M was dipropylene glycol dipelargonate;

Base oil N was a poly(methylphenyl) siloxane (DC 710);

Base oil 0 was a poly(methylpheny1) siloxane (DC 510);

Base oil P is a neutral petroleum oil having a viscosity of 130 SSU at100 F.;

Base oil Q is a neutral petroleum oil having a viscosity of 150 SSU at100 F.

The following table illustrates three greases prepared according to theprior examples wherein sodium metaborate or sodium metaborate andmolybdenum disulfide are incorporated in the grease. The sodiummetaborate is an extreme pressure agent, while the molybdenum disulfideprovides dry lubricating properties. The ureas formed were tetraureasand the data demonstrate that decenylamine; they are compatible with andoperative with the alkali (3) p-toluidme; metal metaborates as well asmolybdenum disulfide.

Table II R R R Grease Composition Grease Properties Sodium MetaborateMoSz, Dnsoeyante B 011 Weighg d Otctnhy-ht Weight D ase percen ra eweigpercent P0 P ropping Denved Fmm Thickpercent Point F.

ener

5 3 9 15 1 240 300 484 5 3 s Q/K 14 2.2 238 300 443 5 3 8 Q/K 13 1.4 5236 288 450 1 Included in this composition were from 1.4 to 2.1 weightpercent of commercial antioxidants and dyes.

2 About 2 parts of Q, per 5 parts of K In order to demonstrate theeffectiveness of the grease prepared using the polyureas, the followingtests were carried out.

The Bearing Life for a particular grease composition was determined bythe following test procedure which is known as the Navy High SpeedBearing Test as described in Federal Test Method 331.1. In this test, aball hearing was operated at 10,000 rpm. continuously for approximately22 hours at the temperature noted in Table III. The apparatus was thencooled to room temperature during a period of 2 hours. This procedure ofoperating at 10,000 rpm. at the not-ed temperature and cool ing wasrepeated until there was bearing failure. The Bearing Life is the numberof hours to hearing failure.

The thickeners were tetarureas, prepared as previously described. Thevarious material used are described hereinafter.

The base oils are identified as the same base oils used in Table Ihereinabove.

In thickener A, the R' and R" were derived from octadecyl-amineidentified here-inabove as Armeen 18 D; the diamine was methylenedianiline; and the diisocyanate was diphenylmethane 4,4'-diisocyanate.

Thickener B was as follows: the R and R" were derived from theoctadecylam-ine identified hereinabove as Ar-meen HT, the diamine wasmethylene dianiline, and the diisocyan-ate was diphenylmethane4,4-diisocy-anate. T-hickener C was prepared as follows: the R and R"radicals were derived from the octadecylamine described hereinabove asAirmeen 18D, the diamine w-as methylene dianiline, and the diisocyanatevvas m-Xylylene diisocyanate.

To demonstrate the use of the polyureas as gellants, a tetraurea wasprepared at 0.7 weight percent in a commercial thinner. A 0.1 weightpercent solution of 1,3- propane diamine (163 ml.), 11.85 ml. of a 10weight percent solution of tall oil fatty amine and 75.2 ml. of a 1weight percent solution of tolylene diisocyanate (as previouslydescribed) (the solvent in each case was the 1 Geometric Mean of 2tests.

ing a viscosity of 480 SSU at 100 F.

Table IV Urea Characteristics Grease Properties Thickener 1 R R B(weight percent) P1 P 0 Dropping Point, F. Derived From 1 In addition tothe thickener, the greases contained from 1.4% to 2.1% by weight, of anoxidation inhibitor.

Table V hereinbelow presents additional data showing the effectivenessof the polyureas as grease thickeners. As prepared, a polyurea was usedin that amount sufiicient to produce a grease having an ASTM workedpenetration (P of approximately 290. The data shows thediisocyanate/diamine mole ratio.

The diisocyanate which was used was an 80/20 mixture of2,4-tolyldiisocyanate and 2,6-tolyldiisocyanate.

The diamine was ethylenediamine, andthe monoamine was Armeen T definedhereinabove.

thinner) was mixed and 50 additional ml. of thinner added. Penetrationfollowing the ASTM method, but using a 23 g. cone, was 331. Thecomposition was a stable gel.

As will be evident to those skilled in the art, various modifications onthis invention can be made or followed, in the light of the foregoingdisclosure and discussion, without departing from the spirit or scope ofthe disclosure or from the scope of the following claims.

We claim:

1. A polyurea of the formula (ll ll R NHTONH-RNH0NH-RNH7 wherein x is anumber having a value from 1 to 3, R, R and R" are hydrocarbon radicalscontaining from 1 to 30 carbon atoms, and R is a hydrocarbon radicalcontaining from 2 to 30 carbon atoms.

2. A polyurea as described in claim 1 wherein x=1.

3. A polyurea as described in claim 1 wherein x=1 and the ratio ofcarbon atoms to the number of urea groups is at least about 6:1.

4. A polyurea of the formula u u R'-NH CNH-R"'NI10NH-R-NH7- wherein is anumber having a value of from 1 to 3, R and R" are hydrocarbon radicalsof from 5 to 28 carbon atoms, R and R are hydrocarbon radicals of from 2to 26 carbon atoms.

5. A tetraurea of the formula o R NHiiNHR NH NHR NH NnR NHiiNHR whereinR and R are hydrocarbyl of from 5 to 28 carbon atoms, and R and R arehydrocarbylene of from 2 to 26 carbon atoms.

6. A tetraurea according to claim 5 wherein R and R are from 6 to 25carbon atoms and R and R are from 2 to 18 carbon atoms.

7. A tetraurea according to claim 5 wherein R and R are alkyl of from 10to 20 carbon atoms.

8. A tetraurea according to claim 5 wherein R is an alkyl radical offrom 10 to 20 carbon atoms and R is an aryl radical of from 6 to 12carbon atoms.

9. A tetraurea according to claim 5 wherein the ratio of carbon atoms tourea groups is at least 6:1.

10. A tetraurea according to claim 5 wherein the sum of the carbon atomsof R and R is in the range of 10 to 30.

11. A tetraurea according to claim 5 wherein the sum of the carbon atomsof R and R is in the range of 10 to 30, the sum of the carbon atoms ofall of the R and R is in the range of 12 to 40 and the ratio of carbonatoms to urea groups is at least 6:1.

12. A tetraurea according to the formula 0 o 0 R NHt lNHR NH NflR NlINliR NH NfIR wherein R and R are hydrocarbyl of from to 28 15. Atetraurea according to claim 12 wherein R is tolylene and R is ethylenediamine.

16. A tetraurea according to claim 12 wherein R and R are aliphatic offrom 10 to carbon atoms and R is tolylene.

17. A tetraurea according to claim 12 wherein the ratio of carbon atomsto urea groups is at least 6:1.

No references cited.

NICHOLAS S. RIZZO, Primary Examiner.

1. A POLYUREA OF THE FORMULA